By September Ms Gillard would also have been in charge for more than three years – a full term – demonstrating her ability to successfully manage a minority government.

It also shuts the door on a potential challenge from former Prime Minister Kevin Rudd.

"It's probably the reason why she only talked to her closest colleagues and the independents," says Ms Curtin.

"She didn't consult Cabinet before making this call, and I would imagine that's partly because she didn't want Rudd's backers to know what she was doing in advance."

Some questioned the timing of the announcement, coming in the midst of major flooding in Queensland and not long after bushfires burned through much of the country's southeast.

But Ms Curtin says most of the disaster management is left up to individual states, and doesn't affect national politics as much as it would here in New Zealand.

"It seems like it's a national crisis, but it's particular states, and it's actually the state government leaders' roles to manage these crises. Prime Ministers will step in and offer support and sympathy to the victims and the homeless and to the governments of those states, but ultimately the job is for the governments of those particular states."

Another reason for Ms Gillard calling the election now is that it forces the opposition to make a choice whether to stick with the unpopular Tony Abbott, or give someone else a go.

"She's 10 points ahead of Tony Abbott, so that's a good thing for her personally," says Ms Curtin.

"She's on 46 [percent] approval, he's on 34. This calling locks Tony Abbott in as leader of the opposition probably, or it forces the Liberals to make a call on whether or not they should leave his as leader or install somebody else – but he's very unpopular with the public.

"But in terms of this two-party preferred vote… she's still behind. The Liberals have around 52 percent in the polls, compared to Labour's 48, so she's got a lot of work ahead of her."

Ms Curtin says despite Ms Gillard's popularity and the tight polls, Labour only has a small chance of winning the election because they cannot afford to lose a single seat that they currently hold.

"She has no seats to lose – so her government can only win seats. That's all they can afford to do and that's very hard to do."